Thread-cutting tool.



EEIHRGEFY,

THREAD CUTTING TOOL.

APPLIOATIOE FILED JUNE 12, 1908. wwas Patented Nov. 9, 1909.

2 SHEETS-SHEET 1.

w. MURGHBY.

THREAD CUTTING TOOL.

APPLICATION FILED JUNE 12, 1908.

939,735. Patented Nov. 9, 1909. 2 SHEETS-"SHEET 2.

'UCIIIHCESCfi inventor Httsrncgs WILLIAM MURCHEY, OF DETROIT, MICHIGAN.

THREAD-CUTTING TOOL.

Specification of Letters Patent.

Patented Nov. 9, 1909.

Application filed June 12, 1908. Serial No. 438,052.

To all whom it may concern:

Be it known that I, WILLIAM Muuonnr. a citizen of the United States, residing at Detroit, county of Wayne, State of Michigan, have invented a certain new and useful Improvement in Thread-Cutting Tools, and declare the following to be a full, clear, and exact description of the same, such as will enable others skilled in the art to which it' course of the thread cut by the chasers.

The die is a complete instrument in itself, of which one part is adapted to engage the end of the tube or rod, and the other part of which is rotary with respect to the first part, carries the cutting chasers, and has attachments by means of which power can be applied to it.

In the drawings :F igure 1, is a side elevation. F i 2, is a longitudinal section at line a-a F 1g. 3. Fig. 3, is a front elevation.

Fig. 4, is'a cross section at line bb of F 1. Fig. 5, is a detail of the feed mechanism. 1 indicates the tubular or barrel part of the machine, adapted to engage over the end of the rod or tube to be threaded.

2 indicates a bushing removable from the barrel 1, and of a size to engage closely around the rod or pipe to be treated; it has an external diameter to engage closely within the barrel 1.

3 indicates a set-screw engaging through the Walls of the barrel 1, and through the bushing 2 against the end of the engaged rod or tube.

The barrel 1 supports an abutment ring 4 fixed to the barrel, and in close engagementof the abutment ring is a feed controlling ring 5. rotatably mounted on the barrel; this is provided with an internal roove G'with camlike projections 6 exten ing into the groove making the depth of the groove at places deeper than it is at other places. The ring 5 may be rotated on the barrel 1 by the hand lever 7-. Through the walls of the barrel are slots in which are inserted thread sections 8 of a sectional nut. These thread sections engage through the slots in the barrel 1 with the thread exterior of a sliding inner tube 9, which is adapted to travel along the interior of the barrel 1. The threaded tubi- 9 has secured to its forward end a head cousistiug of flange 10 on the end of the tube. on which are mounted housings 1]. guides in said housings provided with slots extending radially from the center of the tube 5). At the radially outer end of each housing i an opening through which engages a pin 12 that is secured to a ring 13. which engages within the. circular ring 1% that forms part of the head, and extends back from tho flange 10. The flange 10 supports springs 15, which are interposedbetween the flange 10 and the ring 13. One end of each spring 15 is received in a socket 16 made as a part of the ring 13, and the other end of the spring is held in place by a pin 17 that projects to the rear from the rear face of the flange 10. The outer faces of the sockets 16 bear against the abutment ring 1. There is thus interposed between the abutment ring 4 on the tube 1 and the screw threaded tube 9 a pin carrying ring, which is in sliding engagement with the ring 14, and in rotatirc engagement with the abutment ring 4, and is held to rotate with the head 1-1. The pins 12 are provided on those faces which lie toward the center of the threaded ring with slabbed-oif and inclined faces. The slabhedotf portion between the extreme inner front line 12 and an intermediate point l2 being on a regular incline corresponding to the cone formation that is to be given to the thread that is to be out. At the rear of the point 12", and between the point 12" and the ring 13. there is first a sharp incline from I 12 to 12, and from 12 to 12 a slabbed-ofi' portion that is parallel to the axis of the threaded tube 9. Against the inner face of each pin 12 engages the rear or outer end of a chaser 19 provided on its radially inner end 20 with chaser cutting teeth, and on its outer end 21 with a face that is inclined to correspond to the first incline of the pin 12. The chaser is held in the housing 11, and is pressed to the radially outer part of that housing by a spring that is inserted in a hold ing bracket 22, and presses obliquely against the side of the chaser, tending to press it outward radially, and to hold it 1n constant ring 26 rotates freely around the head in one direction, but carries the head with it when it is itself rotated in the opposite direction.

A tube or rod inserted through the bushing 2 with its end brought into osition between the chasing cutters, is easi y threaded by forcibly rotating the head around the tube which is held in the bushing, and is driven forwardby the interaction of the screw threaded portions of the tube 9 and the tube 1. alon the rod or tube until the chaser passes ofl' from the inclined surface from 12 to 12", the chasers suddenly expand into the cavity made by the more deeply slabbed otf portions from 12 to 12, and the cutting head is projected be 0nd the end of the tube by the recovered orce of the spring 15, which. has been compressed during the cutting action, this action taking place as soon as the sectional nut has been expanded by turning the ring 5 by means of the handle 7. As will be understood, the sectional nut is not expanded'to disconnect the feed screw connection until after the rod or other similar work has been removed from the work engaging part, so that the work can be removed from the head without backing off the cutting tool and retracing the entire course of the thread cut by the chasers. The extent to which thethread cutting operation is carried may be regulated by means of the regulating pin 27 this is a pin which extends through the flange 10, and is provided with a head 28 that engages behind a collar 29 on the abutment ring 4. The end 30 which projects through the flange 10 is threaded and provided externally with a knurled nut 31, and by means of the bolt and nut thus held and thus engaging the movable parts of the tool, the initial location.

of the flange 10 and of the chaser cutters carried by it may be regulated, with respect to the final throw-oft osition, and the extent of the run of the t read produced may be thus predetermined by the user of the tool.

The inner end ofthe chaser carrying me1nher 9 beyond the threaded portion isfinished with a cylindrical portion 9, that engages closely within the tube 1, and revents the chips and dirt from the work rom fouling \Vhen the chasers have advanced the feed screw or the sectional nut, and the feed screw is ke t clean and its life period greatly increase What I claim is 1. In a thread cutting tool, the combination of a work engaging part, a head engaging said part with a feed screw connection, means for connecting and disconnecting the feed screw connection, chasers carried by the head, a ring on the work engaging part pro- .vided with pins to engage the chasers, said pins having inclined faces and recesses to permit the chasers to withdraw to clear the work, and springs engaging the head and said ring to return the chaser carrying head to its initial position upon the disconnection of the feed screw connection.

2. In a thread cutting tool, the combination of a work engaging part, a-head engaging said part with a feed screw connection, means for connecting and disconnecting the feed screw connection, chasers carried by the head, means carried by the work engaging part to engage and adjust the chasers, said means being constructed and arranged to permit said chasers to withdraw clear of the work, and said chaser carrying member being movable longitudinally relative to said means, and means to return the chaser carry ing headto its initial position upon disconnection of the feed screw connection.

In a thread cutting tool, the combination with a work engaging part, a head, chasers mounted in said head for radially sliding movement, pins to engage the chasers, said pins being provided with inclined faces and with recesses at the rear of said inclined faces to permit the chasers to withdraw ra-v dially to clear the work, said chaser carrying member being movable longitudinally relative to said pins, means to retain the chasers in their position when withdrawn clear of the work, and means to return the head to its initial position.

4. In a thread cutting tool, the combination of a work engaging part, a h ead engaging said part with a feed screw connection,

means for connecting and disconnecting the feed screw connection, chasers carried by the head, means carried by the work engagin' draw clear of the work, and means to return the chaser carrying head to its initial position upon the disconnection of the feed screw connection.

In testimony whereof, I sign this specification in the presence of two witnesses.

' WILLIAM MUROHEY.

Witnesses:

CHARLES F. BURTON, WILLIAM M. SWAN. 

